Levo-alpha-acetylmethadol (LAAM) has been shown to be a safe and effective alternative to methadone in the maintenance treatment of heroin addicts. LAAM's longer duration of action (48-72 hours) may provide a more comfortable and effective method of detoxification from heroin than methadone with its shorter (24-hour) duration of action. Hence, it should be tested against methadone to evaluate its clinical utility. Clinical experience has also shown that the current detoxification regimen (16-21 days) may be too short to allow an addict to detoxify from both heroin and methadone, which must be done sequentially in order to end treatment drug free. As such, a longer course of treatment (e.g., 42 days) should be evaluated against the standard 21 day treatment. The specific purpose of this study is to evaluate the clinical utility of LAAM versus methadone as a heroin detoxification agent and two lengths of treatment duration (21 and 42 days). It is hypothesized that the longer course of treatment will result in greater "success" in detoxifying addicts from heroin and that LAAM will be a more comfortable, effective agent than methadone in that process.